SEGUIN, Texas – Gone for decades, a flesh-eating parasite has returned to Texas.
And while the New World screwworm poses an obvious threat to the state’s cattle industry, a rancher and manager of a livestock auction is concerned but hopeful.
Screwworm flies lay eggs in the wounds or body openings of warm-blooded animals, including livestock, wild animals, pets, occasionally birds, and in rare cases, humans. After they hatch, the larvae burrow into their hosts as they eat their flesh. As more maggots are born, the wounds become larger, and the parasites can cause serious, often deadly damage to their hosts if they aren’t treated.
The U.S. Department of Agriculture on Wednesday confirmed screwworm larvae were found in the umbilical area of a three-week-old calf in La Pryor, roughly 100 miles southwest of San Antonio and 50 miles from the border.
The state veterinarian has since set up a 12-mile “infested zone,” quarantining all warm-blooded animals inside of it unless they’re inspected first. U.S. Secretary of Agriculture Brooke Rollins said millions of sterile flies have been released in the area, on top of the regularly scheduled releases.
Historically, the New World screwworm was an annual warm-weather scourge of cattle ranchers from at least the 1930s through the 1960s, until the U.S. eradicated the pest by breeding sterile male flies and dropping swarms of them from planes to mate with wild females. Screwworms were declared eradicated in the United States in 1966, though there were still outbreaks into the 1970s. The deadly flies were detected in Mexico late in 2024, after years of being contained at the southern end of Panama.
Luensmann, a rancher who remembers the screwworm threat from his childhood, shared his experiences: “Anything that was born…if it had an open wound, you’d have to catch it. And there was a purple salve that we would have to run on rub on over it, and it would kind of seal it off and kill whatever was in there,” he recalled. “And I mean, that was twice a day, seven days a week.”
Despite the reported screwworm case being far enough away for now, Luensmann expressed concerns about potential impacts on his auction business. “If it keeps migrating and migrating, and they keep swallowing up more counties, you know, you can see buying companies stepping back. And it’s like they’re going to associate, you know, ‘maybe we don’t need to own, be buying no cattle right now,” he said. “It could make beef prices higher, and it could crash the cattle market, too. We do not know what the effects of this is going to be.”
If the problem escalates, Luensmann fears it could discourage ranchers already struggling to stay afloat. “In the cattle business, you wait nine months for that calf to be born. And then the last thing you want to see is it be eaten from the outside in, in the course of two weeks after being born. I mean, the older you get, the harder it is to lose ‘em,” Luensmann reflected. “So, you know, like I said, if it came down to me — if it got as bad as it did back in the 70s, I might even get out. I don’t know.”
Secretary Rollins has stressed that screwworms do not cause a food safety issue and that animals treated early enough can recover. “If we all work together and follow these treatment and movement restriction guidelines, there is no reason to believe that this incursion will result in any sort of establishment of the pest on our side of the border which is different from when it hit us in the 1950s and the 1960s,” Rollins emphasized.
The Associated Press contributed to this report.
